Ignition control apparatus



Feb. s, 1938. J, L, ARTHUR 2,107,266

IGNITION CONTROL APPARATUS Filed May 3, 191 54 2 Sheets-Sheet 1 RETARDADVANCE a! 20 a: 62 f2? 28 2 I6 .72 go 24 .30

'T Z? 7K w' -25 6 23 u l .7; J 22 73 72 INVENTOR 2/ JameaL.dr//urATTORNEYS Feb. 8, 1938.

J. L. ARTHUR 2,107,266

IGNITION CONTROL APPARATUS Filed May 3, 1934 2 Sheets-Sheet 2 ATTORNPatented Feb. 8, 1938 UNITED STATES PATENT OFFICE 2,17356 IGNITIONCONTROL APPARATUS Application May 3, 1934, Serial No. 723,643

4 Claim.

This invention relates to ignition timers for internal combustionengines and more particu larly to a timer-distributor unit having acircuit interrupter, and a shaft driving the interrupter and means foraltering the angular relation of the interrupter and driving means inaccordance with engine load conditions.

One of the objects of the present invention is to simplify theconstruction, as well as provide controlling means for ignition timers,that is automatically actuated, either directly or indirectly by theengine for advancing and retarding the spark in accordance with thepower curve of the engine.

One manner of securing the above objects is to provide an ignitionsystem, wherein an engine suction operated device, which isautomatically operable in accordance with the load upon the engine, isassociated with devices which include means adapted to effect theadvancing and retarding of sparking impulses in the ignition circuitdiflerent degrees, upon equal increments of movement of the suctionoperated device.

These devices which include the means for effecting this variation inthe advancing and retarding of the sparking impulses in the ignitioncircuit, are so constructed that the degree of variation in theadvancing and retarding of the sparking impulses is directly inaccordance with the load condition upon the engine, so that theignitionmay be supplied to the engine at such times ,as may be found tobe most advantageous, in accordance with the load under which the engineis running, and also in accordance with the power curve of the engine.

A further object of the invention is to provide suitable mechanicalconnections for ignition timers and their controlling devices that thespark timing control may be caused to follow the power curve of aparticular type of engine as closely as possible in the advancing andretarding of the time of occurrence of the sparking impulses. This isaccomplished by the use of super-imposed brackets mounted upon the shankoi the distributor, one of which is pivotally mounted on the timer unitandsupports the suction operated control means, while another bracket isrigidly mounted on the timer unit and provides for an articulatedconnection between the rigid bracket and a movable element of thecontrol unit. That articulated connection includes cam means cooperatingwith a cam-follower, and connected by smmbre means to the movableelement of the suction device. 1

A further object is to produce an efficient and economical mechanicalcoupling for diaphragm movement in suction automatic distributors.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

Fig. 1 is a view embodying the present invention showing the suctionmeans in section, and its connection to the timer, with the distributorcap of the latter removed.

Fig. 1A is a sectional view taken on line- |A--IA of Fig. l, andillustrates the hold-down means for the unit. 7

Fig. 2 is a view partly in section and partly in elevation takensubstantially on line 22 of Fig. 1.

Fig. 3 is a fragmentary sectional view taken on line 3-3 of Fig. 2further illustrating the cam and follower relation.

Fig. 4 is a view similar to Fig. 1, showing a modified form of thepresent invention.

Fig. 5 is a view partly in section and partly in elevation takensubstantially on line 5-5 of Fig. 4.

Fig. 6 is a detail view in section, substantially as indicated by theline and arrows 5--6 of Fig. 4.

It is well known in the engine art, particularly of the combustion andexplosion type, that engines of diiferent makes have different powercharacteristics. That is, what is known as the power curve of theengine, is afiected by a great many different conditions, such asdimensions of the fuel intake and exhaust manifolds, the area in thecombustion chamber, piston displacement, engine produced fluid pressureswithin the fuel pipe and chambers, and many others.

Due to these various conditions which are present in different makes andtypes of engines, it has been found that the time of occurrence of thesparking impulses during operation under different engine loads, shouldvary substantially in accordance with the power curve of the particulartype of engine to which the ignition system is to be applied. That is,in certain types of engines, a much greater degree of advance of thesparking impulses will be required to give a corresponding equalefiiciency from a power stand-point than will be required for certainother types of engine.

In the coupled relation of the engine or power plant to the road wheelsof the vehicle, the power curve then will be somewhat analogous to theload conditions of engine operation, and the control effected by theengine produced suction device will be in part at least a control inaccordance with the engine load conditions.

In the present improvements, the power curve of the engine is firstascertained by suitable dynamometer or other appropriate tests by whichdata is obtained showing the setting of the timer which is required inorder that the engine will give the maximum of power at a given load.The curve of maximum power, showing the setting of the timercorresponding to the load is plotted on coordinate paper from the dataobtained, and this power curve is used so as to enable the mechanism,which will be described hereinafter, to be constructed in accordancewith the requirements of the particular type of engine in order that themaximum power may be produced for any given load.

This mechanism is combined with an engine suction operated device, whichis controlled by the load of the engine, and this suction device willtend to actuate the aforesaid mechanism in such a manner as to provideignition at the time it will accomplish the most effective combustion ofthe engine charge, both in accordance with the load of the engine, andthe power curve of the engine.

The ignition timer-distributor comprises a housing 20 provided with ashank 2| received Within an opening 22 of the engine base 23. The shank2| provides a bearing for a shaft 24 that carries a gear meshing with agear driven by the engine, both of which are not shown. The shaft 24drives a weight supporting plate 25 carrying the pivot pins 26 thatpivotally support weights 21. The pins 26 are connected by springs 28with pins 29 carried by an arm 30. The arm 30 is fixed to a cam shaft 3|pivoted on a reduced extension of the shaft 24, and has cam facesengaging extensions of the weights 21. The springs thus tend to move theweights 2"! inwardly toward the cam shaft or sleeve 3| mounted on theupper portion of the shaft 24.

The housing 20 supports an interrupter plate 32 carrying a pivot stud 33upon which a circuit breaker lever 34 is pivoted. The interrupter plate32 carries a stationary contact 35 that cooperates with a movablecontact 36 carried by the lever 34. A rubbing block 31 and one end of aleaf spring conductor 38 are mounted on the lever 34, the other end ofthe spring 38 being attached to an insulated terminal 38. The rubbingblock 31 is operated by a cam 48 formed integral with the sleeve 3|.

If the housing 20 is rotated about the axis of the shaft 24, the angularrelation between the rubbing block 3'! and the cam 40 will be varied inorder to vary the timing of the ignition. The timing of the ignitionwill be varied also by changing the angular relation between the sleeve3| and the shaft 24; this change being effected centrifugally by themeans responsive to engine speed including the weights 2'! and theassociated mechanism. It will be understood that the circuit interrupterterminal 39 is connected to the primary winding of an ignition coil andthat the distribution of sparking impulses generated by the coil iseffected by distributor apparatus comprising a distributor rotor 4| thatcooperates with a central terminal 42 and a circular row of terminals43, the former being connected with the secondary winding of theignition coil and the latter terminals 43 being connected with theengine spark plugs. The terminals 42 and 43 are carried by anoncondueting cap 44 cooperating with the housing 28 to enclose theignition timing and distributing apparatus.

Other means for automatically controlling the timing of the ignitioncomprises a suction chamber 50 made of sheet metal parts 5| and 52enclosing and supporting afiexible diaphragm 53, the edges of which areclamped between peripheral portions of the parts 5| and ,52. Thediaphragm 53 is connected by a rivet 54 with a cup shaped washer 55 anda. bar 56. The diaphragm 53 is held in the position shown in Fig. l by aspring 51 that bears at one end against the washer 55 and at the otherend against a coupling 58 threaded at 58 into a bushing 60 carried bythe part 52. The coupling 58 is adapted to receive a pipe 6| attached byconnections 62 to a threaded opening 63 in a carburetor frame 64. Theopening 63 communicates with a port 65 drilled through the carburetorframe, which port is at a point near the edge of the throttle valve 66so that when the valve is in the closed or idle position the port willbe on the engine side of the valve 66, and so that when the valve isopen to any point beyond idling or low engine speed the port will be onthe carburetor side of the valve. The valve 66 is mounted on a shaft 61that is operated in any suitable manner.

-The part 5| of the suction chamber 50 is attached by studs 68 and nuts69 to a bracket 10 having a portion 1| pivoting about the shank 2| ofthe ignition timer housing 20 and resting upon a finished surface 12provided by that portion 13 of the engine frame that provides theopening 22 for receiving the shank 2|.

Mounted upon the shank 2| and in super-imposed relation with part ll ofbracket 10 is a bracket 14 that is adapted to be clamped to the shank byscrew 15 and nut 16. Pivotally secured by a screw 71 and a nut 18 to anextension 19 of the bracket '10, is a cam follower or lever 88 thatcarries a roller 8| disposed in a cam slot 82 in an extension 83 of thebracket 14. This assembly is slidably held together by a screw 84 and anut 85 as illustrated in Fig. 3. The bar 56 which is attached to thediaphragm 53 has a bifurcated end 56 that straddles the cam follower 80,and is secured thereto by a pin 86 passing through and cooperating witha cam slot 81 formed in the cam follower.

In operation; when the throttle valve 66 is closed or substantiallyclosed as in engine idling the vacuum at the port 65 will be relativelyhigh, thus overcoming the spring 51 causing the diaphragm 53 to moveupwardly as viewed in Fig. 1. As the diaphragm 53 moves upwardly orcompresses the spring 51, the bar 56 also moves causing the lever 88 topivot about the screw 11 and move the roller to the inner end of theactuator or cam slot 82. This causes a relative angular movement ofbrackets 18 and 14 that results in shifting the housing 20 relative tothe shaft 24, thereby causing the ignition circuit interrupter to bedisplaced angularly relative to the cam 40.

The present ignition apparatus is provided with three or more sets ofmeans for controlling the ignition timing; namely, means for controllingin accordance with variations in engine speed, means for controlling inaccordance with variations in engine load and/or engine producedsuction, and means for manually controlling in order to suit othervariations in operation.

Manual control of the spark timing cam can be effected by moving aBowden wire 88 attached aromas at l! to an extension I. of the bracketII, the Bowden wire being incased in a flexible tube 90. To provide foroscillatable movement the bracket II is held down upon the engine frame23 by a screw stud 9i threaded into a tapped hole in the engine frame23. The head of the screw stud 8i passes through an arcuate slot 92 inthe bracket Ill and retains a spring 93 bearing against a washer 94which bears against the bracket II.

Referring to Figs. 4, 5 and 6, which show a modification of the previousforms, suillx "0 will be added to the reference characters forindicating similar parts. It is deemed unnecessary to describe structureother than those features illustrating the modifications in the secondform. With particular reference to Fig. 4, bar 560 has a right angleportion Hill for cooperation with a cam element llll integral with abracket "a which is adapted to be clamped to a shank Ila by a screw 15a.and a nut 16a. Formed upon the bar 56a is a rib portion I02 forfrictional engagement with that portion of the cam element |0l that isadjacent the bar 56a. A coil spring I03 is provided and has one endanchored at I to the bar 56a in close proximity to the angle portionHill. The other end of the spring is anchored to a pin I05 that iscarried by the cam element 10!. The function of the spring being to keepsurface l0l' of cam element llll and surface I00 of angle portion Hillin engaging relation.

In operation, as in the previous form, the high vacuum at the port 65aovercomes the spring 510 causing the diaphragm 53a to move the housing20a. angularly with respect to the unit 500, through the cam elementsI00 and IN. This action causes cam element "H which is integral with theclamping portion 14a. to move in a clockwise direction causing thehousing 20a to be moved relative to the shaft 24a thereby causing theignition circuit interrupter to be displaced angularly relative to thecam 40a. The slot 92a formed in the cam element IOI receives thehold-down screw 9|a surrounded by a spring 93a bearing against a washer94a which in turn bears against the cam element HH, and permits freemovement of the said cam element.

In the instance of both forms of disclosure, the angularity and/or thecontour of the cam portions of the articulated connection, are designedin accordance with the power curves of different types of engines. Anychanges neces sary for adapting the timer and its control unit toengines characterized by different power curves, will involve a changein but one of the physical elements, that being the configuration of thecam part 82 in the first form of disclosure, and the cam part III! inthe second form of disclosure.

Solely for purposes of illustration, and presupposing a specificinstance in which the control means is installed for effecting a retardin spark timing during engine idling conditions, let it be assumed thatthe direction of cam rotation is counter-clockwise as indicated by thearrow A in Fig. 1, and that the port 65 is on the engine side of thethrottle valve 66. It will then be apparent by consideration of Figs. 1and 4 of the drawings, that actuation of the displacement member 53 willresult in oscillating the plate I4 in a counter-clockwise direction,which in turn will carry with it the movable part of the circuitbreaker, thereby causing a delayed occurrence of the spark timingrelation.

On the other hand, presupposing a specific instance in which the controlmeans is installed for effecting an advance in spark timing at enginespeeds above those of idling, then let it be assumed that the directionof cam rotation is clockwise, and that the port 65 is on the carburetorside of the throttle valve. It will then be observed by referring toFigs. 1 and 4 that the displacement member is not actuated until thethrottle valve 66 is opened sufliciently that the port 65 is subjectedto the reduced pressure of the induction pipe. The displacement member53 and its linkage then oscillates the circuit breaker against thedirection of cam rotation, thereby producing an advance in spar timingrelation.

In like manner, by connecting thejsuction chamber ill tothe engine sideof the throttle valve for clockwise rotation of the cam, or? byconnecting the chamber to the carburetor side of the throttle valve forcounter-clockwise rotation of the cam, etc., various other combinationsof spark retard and advance can be obtained,

' and by modification of the camming elementsin the linkage between thedisplacement member and the circuit breaker support, the spark timingcontrol may be made to follow any desired curve of enginecharacteristics.

While the forms of embodiment of the present invention as hereindisclosed, constitute preferred forms, it is to be understoodthat otherforms might be adopted, all coming within the scope of the claims whichfollow.

What is claimed is as follows:

1. In ignition control apparatus for internal combustion engines havinga housing provided with a shank and rotatably supported for altering thetime relation of the engine, the combination with the housing comprisinga plate pivotally mounted upon said shank providing for manualdistributor adjustment, a second plate rigidly mounted upon the shank,and means operatively connecting the plates comprising, a cam slot inthe rigid plate, a cam follower riding in the cam slot and pivoted uponsaid first plate, and a member carried by said first plate and connectedto said cam follower.

2. In ignition control apparatus for internal combustion engines havinga housing with a shank rotatably supported for altering the timing ofthe engine, the combination with said housing comprising a bracketpivotally mounted upon the shank, housing shifting means carried by thebracket, a second bracket having a camming surface formed integraltherewith and mounted upon said shank in juxtaposition with said pivotedbracket, and a reciprocating means connected to the housing shiftingmeans and cooperating with said camming surface.

3. In ignition control apparatus for internal combustion engines havinga housing and a shank rotatably supported for controlling the timing orthe engine, the combination with the shank comprising means for rotatingthe shank on its support, means connecting the rotating means with theshank in order to vary the angular relation of the spark timing, saidconnecting means comprising, a plate pivotally mounted upon said shankproviding for manual distributor adjustment, a second plate rigidlymounted upon the shank, and meansoperatively connecting the platescomprising. a cam slot in the rigid plate, a cam follower riding in thecam slot and pivoted upon said first plate, said rotating means being 0an aperture in registry with the slot, a tension device including a studdisposed in the slot and aperture and threaded into the engine frame, ashifting device carried by the bracket for varying the angular reiationbetween the bracket and arm, means extending from the shiitin; means toengage the cam arm, and mean: causing the cam arm to iollow theextending means upon actuation of the shifting means.

JAMELARTHUR.

